Lever for aircraft controls



May 11,1943. "E. H. scH'ENK 2,441,212

LEVER FOR AIRCRAFT CONTROLS Filed April 27, 1945 2 Sheets-Sheet 1 INVENTOR EDOUA/PD H SCHf/VK ATTORN EY Patented May 11 1948 roe m ee? eeee Edoua d H-fif enk, N York, Y

Re ublic Avia ion Generat on, lie

L e' ret iiee et Application April 27, 1945, Serial No. gauge 5 leielsl 1 2-141?) I t9 e enir ntioeel e lei ererefi e eoe e invention relatesto the controls for LmQY- lerer er t f .1? W i-e99 ii nd i let T 2 199 I L e-b-le airfoils and contemplates .a struct re that will function normally in 'thensua'l and ;,$ta1ndare manner and at the same time include 'normallyinoperative means -for supplyin a .suvnlementali y mechanical advantage to the contm when required. a c

"The present control proposes a normally .in.eferennenl l l Q1194? i Z iective and inoperative auxiliary control jihetin i, no way interferes with the usual and customary operation and functioning of the princip r eentm :but which may :be'brought into-nperatiQn to nunple-ment and augment the-tomes applied by the said principal control i0! the regulation movementofmovahlelairfoiis. Among other objects the instant invention has i in new an auxiliary control operable in econ-lumtion' with the principal ;.or main control for the moi/able airfoils of an eircnaf't to not only initiate the seperaztion of :the principal-1' control when irez'en or immovable by normal or cQnVentiQnemeans :b.ut:a;1so to continue to boost .o augment the forces normally applied 41.0 the lcnntm and thereby assist initne oneratiofi theneof a ter the start or initiation 10f its zme ernent. with the ab ve and other nhieets in wi w, es the appa ent, this invention consists in the aQQDStI'MGfi-Qll, combination" and arrangem nt Q all as hereinafter more iu y-tleseribed, elazimed and illustrated in the accompan in L elrenings, wherein;

' .zri 1 is a more :or less schematic l mtio i the present invention showing the principal @enu o trail lever in its neutral ;or su stantially I men; ra 9? mi k? eal 513931131011 sand, in'phantom iineethe ma l e5 1i ,ti ionera-tive throw of said-control lever, {ohen-xiliary control lever being shown inifuzl lines in fitad fielid I l its inactive or inoperative position; e fle Ele- 2 s a imilar-view illustratin :the fence p v. t min pf zthe'rm ehenice booster Q nu ailin l 1 i9? t -.9 l verit supplement and au ment the forces nerthe we smel y applied to th prin ipal contm z ere for moving it imm its neutral positi n under railenorma or eme en y cond t s t e i neet -re tor i operat ve pos t on of t e auxilia y le er zb lng s wn in 'nhentam .lme end it ac ve or enemt eipesition in tull lines;

:Eig. 3 is e 71 21 1 n w 9.1 th tcontrqk eszerees-siisv Qe in l l n s :in .iFi 1; 2 In the 3 9? ellemezti ehon 1315 Fi -14iseneler tienishow n thezreletireznosi 550111 20 g m e te ee e u 1y 9 tim qf tnegnandles or the tcqntrol and auxil a y lev r Fig. 5 is an elevation, partly in vertical gseQfiiQn ele zli e -1 n :Eie- :5 illustratin the 1812131 ite e @d ta ls sQ the pres nt r wentipn es 399 58 15 em 7..

b 1 elle a l tteptwfe e ee eeed V ygn .wemeisn elm? eipeke nt ard or customary manner. Between the pivotal mounting H and the bolt (4 the lever It may flattened on its opposed sides, as atifl'; f j g On the bolt I4 is also pivoted an auxiliary' lever 1 and the pilot manipulates only the control lever Ill. The auxiliary lever [5-16 then moves in unison with but not relative to the control lever l and therefore does establish contact with the cam l9 by means of the roller ll. Hence the auxiliary lever ll6 does not interfere with the normal operation of the control lever l0 and for allpractical'purposes is non-existent. The slight friction existing between'the flattened sides 10' of the control lever 10 and the oifset inner ends l8 of the fork or work arm 16 of the auxiliary 'lever- [S -l5 ;prevents any accidental relative moyement between these two levers as long as the-.handle l8 is not intentionally moved from to the power arm of the control lever 10 to terminate below the handle l2. At its lower end and projecting laterally therefrom at the bolt the auxiliary lever is provided with a forked work arm 16- having ofiset inner ends 16* straddling the lever l0 and carrying between its free outer ends a roller or cam-follower IT. The upper free end of the power arm I5 is provided with a grip or handle [8 projecting laterally or horizontally therefrom at right angles on the'side thereof opposed to the-control lever l0 and hence this handlelBis located below the handle l2 regardless of the position of the auxiliary lever I'd-l6 with respect to the control lever 10. The relative-arrangement of said grips or handles l2-l 8 is such that the pilot may conveniently grasp only the control lever In or may simultaneously grasp the control lever [0 with one hand and the auxiliary lever -16 with his other hand whereby said levers may be'operated'independently or in unison. 3

; A cam or inclined plane I9 is situated in a 'fixed position relative to the fulcrum H and out of the normal path of movement of the control lever ID or itsassociated'parts but to cooperate with the roller ll of the auxiliary lever 15-16, as shown in Fig. 2, when the auxiliary lever 15- i6 is moved or swung from its inactive or inoperative position; shown in solid lines in Fig. 1 and in phantom lines in Fig." 2, to its full active or operative position, shown in solid lines inFig. 2, to initiate or assist in the movement of the lever H3 out of its vertical neutral position.

f The two parallel branches of the work arm 16 extending beyond the offsets-l6 are braced 'or interconnected adjacent the lever l0 by means of 'a V-shaped rib 20, which also acts 'as a double stop to limit the throw'orangular 'travel of the auxiliary lever l5'l6 relative to the control lever Ill in either direction. '-Preferably (as shown Fig.2) this throw isso limited th'atthe-auxiliary lever- Iii-Hi may move equidistantly upon either side of the mean or central line of the control lever l0 especially in its neutral position as shownin Fig. 1. However it is not necessary to limit the throw of the auxiliary lever l5'-l6 to any angular degree relative to the control lever [0 as that obviously-is merely a matter of design. In Figs. 1 to 3, inc., the pivot II and the cam 19 are shown in section to indicate thatboth are relatively immovable and may be mounted on a common supporting structure preferably a fixed part ofthe aircraft structure. 1 The operation of this form ofthe mechanical booster, constructedand arranged in accordance with the present invention, and shown in Fig. 1 to"4,'in'c., is as follows:

Under normal conditionsQthe auxiliarylever l5-l6 is positioned as shown in full lines'i'n Fig.

. is. or bellcrank having a power arm 15 juxtaposed 'justed andregulated by the usual nut ooacting ,sf dle'or inactive position. The extent of this 'fri'ctional'engagement or contact may be ad- 'roller 11 travels, during the normal operation of the control lever I0, within the confines of a circle Y having the pivot II as its center and cannot, therefore, contact the cam l9 located outside or beyond this circle Y.

-When, however, the control lever I0 is frozen in, or is diflicult to move from, its neutral position, i. e. when the pilot is unable to initiate movement of said lever Hi, the shifting of the auxiliary lever 15-[6 relative to the control lever in augments the normal forces applied to the control lever [6. By using one hand to'manipulate the control lever in and his other hand to move the auxiliary lever 15-16 relatively to the lever I0, the pilot may swing the lever l5-l6 from its inactive position shown in full lines in Fig. 1 .to its active position shown in full lines in Fig. 2. Any movement of the lever l5l6 in the direction of the arrow X out of its idle or inactive position projectsthe roller '11 beyond the independently of the auxiliary lever plane l9 whereupon the continued swinging movement of the auxiliary lever l5-l6 relative to the control lever 10 develops a thrust on' the latter opposed to the resistance of the rod or link l3. This-thrust is in addition to and therefore augments any force applied by the pilot to the lever It! at the handle or grip l2. The additional force resulting from this manipulation of the lever [5-46 combined with force applied directly to' the lever ID at its grip l2 starts or initiates movement of the control lever l0 and this movement of the lever may be continued, in either direction, in the normal or conventional manner [5-46. once the movement of the control lever I0 is started in the direction of the arrow X, the lever usually can be freely swung in either direction and since the auxiliary leverl5l6 then performs no further function nor is it then necessary to this continued movement of the control lever [0, it maybe moved counter clockwise to its idle or inactive position as shown in full lines in Fig. l and in phantom lines in Fig. 2. It is manifest that in that form of the invention illustrated in Figs. 1 and 2, the auxiliary lever l5--|6 in assisting the initiation of movement of the lever l0 always swings relative to the lever [0 from the phantom line position to the full line position in Fig. 2, and, as a consequence, always initially moves the lever Win the direction indicated by arrow X. Once movement of the lever 10 is started it maybe swung in either direction as required by operational conditions of the aircraft. v

-I -Iow'ever, if operating conditions of the aircraft require that the forces normally applied "to the control lever at the grip or handle I2 be increased or augmented after its movement has once begun the pilot may continue the swing- ;ing movement of the auxiliary lever l-5l 6relative to the lever to. This subsequent movement of the lever =l 5-'lii isonly limited by the V-rib or stop 21! and by the length of the cam or incline'd plane 1 9, the design and e'fiec'tive'ness of earlier which may be altered or varied without departing from the spirit and scope hereof. Though the form of the mechanical booster of the present invention shown in Figs. 1 and 2 'is adapted to unfreeze or help start the "active motion of a control lever lfi over a relatively small initial part of "i ts angu lar travel, it will be easily understood by those skilled in the art that this initial angle of adjustment can be increased by increasing the throw o'f the auxiliary lever i 5=--,i 6 and correspondingly lengthening the inclned plane'or "fixed cam "f9. The whole auxilfiary device of the instant invention can readily be adapted to boost manually, not only the initial but also the final motion or the control lever is and by merely duplicating the elements 16- 17 -'l9 on'the 'opp'r isi-te' side of the lever 1 0, this structure can be adapted for boosting a double action control lever in either direction.

In and-6, a specific and detailed adaptation bftheit form of the invention illustrated schematically in Figs. '-1 and 2 is disclosed as appliedto. an aircraft "control lever of the cradle type. "He'rethe stick or control lever is fulcrhmed or pivoted at 41' across the bottom or vertex of a hollow triangular cradle 5|, for ind eperrdentangular motion therein-in the longitud inal plane or the aircraft to control the elevators thereof through a push-pull rod 43. This {cradle 5 1 is also pivoted about the axis of said r'odfl "whereby the stick or lever 40 and the cradle may 'swing in unison in a plane transverse to the longitudinalplane of the aircraft to contrail the ailerons of the aircraft through push- '-pufI-l r'o'ds =(not shown) secured to the cradle by 13011252. "Inthis adaptation a common pivot '44 is provided across the control lever 40 to attach the endsof both the elevaitorrod 43 and the auxiliary lever or ibel-lcran'k 46 to the lever 40. This auxiliary lever 45--4'B comprises an operating arm ifi adjoining the control-lever 40 and a forkedw'o'rk arm 46 disposed angularly to the arm es and straddling said 'controllever 40 after the manner -of"the'work arm 16 in Figs. 1 and 2. The free end dfthe'work arm '46 carries a roller carer-cooperation w i'th a disk #9 which is the full equiva'lent in-flmotion and operation of the cam 9brincline'd plane 'in Figs. l and'2. A V-shaped rib "50 braces the branches of the forked arm s6 and acts as a double stop to limit the angular throw-of the aluxiliary'lever -46 relative to the c ontrol stick 18.

A pair-of aligned hollow trunnions '53 are formed or'si-tuatedon-the upper'partof the cradle E- l whereby the latter is mounted for swinging movement about the axis or "the rod 4 3 in the hired, split journals-54. Suitable thrust ball bearings -55 may be interposed between the journals 5'4 and the trunnions fit' according to standard practice. The halves "of each bearing M are united by means of bolts -56 and'the whole cradle and bearing assembly is fastened in an opening ofthe' c'ockpit floor' of "the "aircraft in the-coniveritiorial manner;

' 'iheilisk l il whichc'o'acts with theroller 41 upon the operation of the auxiliary lever 45-46 hasa 'soli'd cylindrical body 59 which forms atran'sve'r'se boosters.

partition at the inner end ofone of the trunnions 53 "and is fixedly secured to said trunnion in any suitable manner to withstand any loads to which it may be subjected during the operation o' f the auxiliary lever 45-45.. The upper half of the disk is provided with a mounting flange 5!- -rfi'tting over the edge of the eoa'ctin'g trunnion 53 and its lower half is provided a slanting projection or lip '58 resting against the inner suriaceof the corresponding inclined side of "the cradle '51. Thus any load appliedto the disk 19 by the roller t? during the operation 01- the auxiliary lever 45 cc (as shown Fig.5) is uniformly distributed to the periphery ofisaid disk andis directly transmitted through the trunnion '53 and the thrust hearings 55 to the fixed structure of the aircraft.

The'end of the rod #3, is equivalent of the rod or link I 8 in Figs. 1 and in function and operation, is pivotally mounted on a cylindri'cal bushing Bil and that in turn is mounted with a close fit on acrosspin fi l forming thercomm'on vpivot its of :said rod and for the auxiliary lever dd-d6. The two opposite ends 62 .of said pm at are square in cross rs'e'ction and project heyonzd the flattened portions or faces of the control lever lit) to 'be received in scorresponding square holes 53 provided in the forked :work arm t5. The roller "El is hivotally mounted on :a'fixed pin or pivot 88, which :also has squared send ."portions at projecting into corresponding l-square holes fi l provided :at the'free ends of the branches of the work arm 816. lheznigid :iraine thus formed by the two branches of the work :a-rmloriork Q6 and the two parallel pinst i and this efurther reinforced'by the VI-shaped rib 15.0 functioning vas does the similar rib 2 9 in Figs. 1 and .2. i

A conventional mortise B1 is provided in the control lever All .to receive the end of the mod 43, while :a hole or opening 68 is ipnovidod' in the inclined opposed wall :of the hollow cradle .51 to ive passage or clearance for the roller 4:1 when the control lever 410 swings fore {and aft during its normal, unassisted 'operation.

As in that :form of :the invention shown in Figs. i and 2, the arrangement of the centers of the 'disk 39 and of the pivot the pivotal axis 'of the cradle 51] is such that the auxiliary lever l 5 and its roller 4:! do not interfere with the normal fore and aft operation :of the lever =40 nor is the transverse normal swinging motion of the cradle 51 by means of :the stick 40 for the adjustment of the ailerons modified or interfered with by the auxiliary lever and its associated parts. When, -however, :the auxiliary lever --4546 is swung relatively to the lever i4!) rinthe manner described in 'connectionwithffigs. 1 toe the roller =47 cor'ita'cts the disk 49 zand develops a thrust on the lever "4 0 opposed to the resistance {of the rod #3 thereby initiating :andyor assisting in the movement of said "lever. Manifestlyil ligs. 5 and 6 illustrate a detailed developmentof theinvention I graphically disclosed'in' Figs. 1 ,to .4 and 'beyond various minor variations in :zdetails and rapplicationthe'opera'tion andfunctioning of the two are identical. A

The structure shown and described-herein may "readily be adapted to any aircraft not otherwise provided with emergency;power :means :for funfreezingthe control lever'ormayzbefaddedto said a power means as a precautionaryzauxiliary safety device for use in "case of failure of said power Many modifications and variations 'of'thezpresreadily; conceivable but in no sense depart from the principles herein defined and set forth in the appended claims. What is claimed is:

'1. The combination with a pivoted control lever having a portion for themanual operation thereof, of an abutment situated adjacent said lever, and an auxiliary lever, also having a portion for the manual operation thereof, and pivoted to swing relative to said control lever into and out of contact with said abut-ment to initiate movement of the control lever about its pivot.

2. The combination with a supporting structure, of a control lever fulcrumed to said structure, and a mechanical booster comprising an abutment fixedly mounted on said structure, and an auxiliary lever pivotally mounted on said control lever and swingable about its pivot relatively to said control lever to contact said abutment and thereby augment the forces normally applied to and moving said control lever.

3. The combination with an aircraft structure, ofa control lever pivoted thereto, and a mechanical booster comprising a fixed abutment secured to the aircraft structure to lie without the normal pathof movement of said control lever and its associated'parts, and an auxiliary lever mounted on the control lever for pivotal movement in a plane parallel to the plane of movement of said control lever and movable relatively to said control lever to contact said abutment and thereby supplement a force normally applied to said control lever for its operation.

4. The combination with an aircraft, of a pivoted control member, and a mechanical booster comprising a stationary abutment mounted on said aircraft adjacent to and without the path of movement of said control member, and an auxili'ary lever pivotally mounted on said control member to swing relatively thereto and thereby project a part of said auxiliary lever beyond the path of movement of said control member for riding contact with said abutment.

The combination with an aircraft structure, of 'a control lever pivotally mounted on said structure, a stationary abutment fixed to said aircraft structure adjacent to and without the path of movement of the control lever, an auxiliary lever pivotally mounted on said control lever in alignment with said abutment to normally rest adjacent to said control lever, and a lateral arm fixed to said auxiliary lever to be projected beyond the path of movement of the control lever by the movement of the auxiliary lever relatively to said control lever and thereby contact and progressively bear against said abutment.

6. The combination with an aircraft having a movable control surface, a pivoted control lever and an operating connection between said lever and said control surface, of a stationary abutment adjacent said control lever in apposition to said connection, an auxiliary lever mounted on said control lever for movement either relatively to or in unison with said control lever, and a normally inactive arm fixedly secured to said auxiliary lever to contact said abutment upon the movement of said auxiliary lever relative to the control lever and thereby develop a thrust on said control lever opposed to the resistance of said operating connections.

'7. The combination with an aircraft having a movable control surface, a pivotally mounted control member, and an operating connection'from said member to the control surface whereby the lattermaybe operated by the former with a given mechanical advantage, of an auxiliary lever pivotally mounted on said control member to normally rest adjacent and be movable relative thereto, an arm fixedly secured to said auxiliary lever to project laterally with respect to both said member and lever, an abutment fixedly mounted on said aircraft without the normal, inactive path of movement of said arm, means for swinging said auxiliary lever relative to the control member to project the extremity of said arm beyond the aforesaid path of movement, and means of cooperation between the abutment and the extremity of said arm effective upon the projection of the extremity of said arm beyond said path of movement to thereby develop an additional and supplemental mechanical advantage for said control member.

8. In an aircraft control mechanism the combination with a pivoted control lever, of means for connecting said lever to a movable airfoil, an angularly formed auxiliary dever mounted at its elbow on said control lever for pivotal movement relative thereto, means to limitrthe movement of said auxiliary lever relative to said control lever, a stationary cam mounted opposite the angularly disposed lower extremity of said auxiliary lever, a cam-follower carried by the angularly disposed lower extremity of the auxiliary lever, and means i or moving said auxiliary lever relatively to the control lever and thereby project the cam-follower into operative contact with said cam to develop a thrust on said control lever in opposition to the aforesaid means connecting it with a movable airfoil.

9. In an aircraft control mechanism the combination with a pivoted control lever, of a pushpull rod system pivotally connected to said control lever for the operation of a movable airfoil, an auxiliary lever in'the form of a bellcrank mounted at its elbow on said control lever for pivotal movement about the pivot constituting the connection between said push-pull rod system and the control lever whereby one arm of said auxiliary lever normally rests adjacent said control lever and the other arm projects laterally therefrom and at an angle to the control lever, a roller rotatably mounted at the free end of said laterally projecting arm, a stop carried by said laterally projecting arm of the auxiliary lever to limit the movement of said auxiliary lever relative'to the control lever in either direction, a member eccentric tothe pivots of the control and auxiliary levers, and means to swing the auxiliary lever about its pivot and relative to the control lever to establish operative coaction between said roller and said eccentric member to develop a thrust on the control lever in opposition to the resistance of the pushpull rod system aforesaid,

10. The combination with a unitary control mechanism for the adjustment of the movable airfoils of an aircraft, of means for increasing the normal operative power of said control mechanism comprising a normally inoperative auxiliary mechanism adjustable independently of said control mechanism, and stationary means reacting with said auxiliary mechanism upon its independent adjustment to develop n additional thrust in the control mechanism opposed to the resistance of the movable airfoils.

11. The combination with the unitary control "mechanism for the adjustment of the control surfaces of an aircraft, of means for additively increasing the normal operative power of said control mechanism comprising an auxiliary mechanismmounted for movement independently of and relative to said control mechanism, and means associated with said auxiliary mechanism to react therewith only upon its movement relative to the controlmechanism and thereby supplement and augment the power of the control mechanism normally applied in opposition to the resistance of the aforesaid control surfaces.

12. The combination with a control lever for the adjustment of the control surfaces of an aircraft, of means for increasing the operative effectiveness of said control lever, comprising an auxiliary lever pivoted to said control lever for movement relative thereto, means under the control of said auxiliary lever to be projected laterally from said control lever upon the movement of the auxiliary lever relative thereto, and stationary means reacting with said last means when projected laterally as aforesaid to thereby supplement and augment the thrust of the principal control lever in opposition to the resistances of the control surfaces.

13. The combination with a conventional control lever for the adjustment of the control surfaces of an aircraft, of means for increasing the operative effectiveness of said control lever comprising an auxiliary lever pivoted to said control lever for movement in unison therewith or relative thereto, an arm under the control of said auxiliary lever to be projected laterally from the control lever upon the movement of the auxiliary lever relative to the control lever, and a fixed abutment to contact and react with said arm when projected laterally as aforesaid to thereby supplement and augment the thrust of the control leVer in opposition to the resistances of the aircraft control surfaces.

14. The combination with a control lever for the adjustment of the control surfaces of an aircraft, of means for increasing the operative effectiveness of said control lever comprising an auxiliary lever pivoted to said control lever for movement in unison therewith or relative thereto, a stationary abutment adjacent to said control lever, and an arm fixed to said auxiliary lever for movement therewith to be projected laterally from said control lever upon the movement of the auxiliary lever relative thereto to contact said abutment and thereby develop a thrust on the control lever in opposition to the resistance of the aircraft control surfaces.

15. The combination with a control lever for the adjustment of the control surfaces of an aircraft, of means for increasing the operative effectiveness of said control lever comprising an auxiliary lever pivoted to said control lever for movement in unison therewith or relative thereto, a stationary cam abutment adjacent to said control lever, and an angularly disposed arm fixed to said auxiliary lever for movement in unison therewith and normally occupying a position out of possible contact with said abutment and to be projected laterally from said control lever upon the movement of the auxiliary lever relative thereto to contact and operate over said abutment and thereby supplement and augment the thrust of the control lever in opposition to the resistance of the control surfaces.

' EDOUARD H. SCHENK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name 7 Date 433,978 Corning Aug. 12, 1890 912,595 McClaren Feb, 16, 1909 1,455,431 Dicks May 15, 1923 1,689,648 Voleske Oct. 30, 1928 1,998,362 Dodson Apr. 16, 1935 2,037,551 Vischer Apr. 14, 1936 2,053,950 Franklin Sept. 8, 1936 

